I think he already has the 6 CD changer attached, so I dont know if the adapter would work.

In that case, maybe you can even skip the adapter: Tap into the audio lines coming from the CD changer, and use a stereo A/B switch to toggle between Empeg and CDs. Whenever you want to listen to the empeg, you'd need a CD running in the changer... If you wanted to get really fancy, use the Sony XA-39 II and have it trigger off the empeg's Amp Remote line so that you simply have to power up the empeg to make it switch the inputs...